Human voice controlled machines are known in the art as are remote control systems for welding equipment. U.S. Pat. No. 4,216,367 to Riseberg, issued Aug. 5, 1980, entitled "Wireless Remote Control for Electric Welder", discloses a welding machine which can be remotely controlled. The welding machine has a controllable power supply which is initially set by the human operator to provide a desired power level using a main rheostat. An operator, working at a location remote from the welding machine, carries a pen-type adjustable rheostat which carries calibrations indicative of various percentages of the preset welding current. If the human operator wishes to change the magnitude of the welding current, he need not return to the main rheostat at the welding machine, but instead sets the remote rheostat between the electrode holder and the workpiece. A current transformer in the welding machine senses the output (calibrating) current flowing through the welding cable. A signal proportional to the desired welding current reference is compared with the stored value of the present welding current reference, to produce the control signal, which is fed to an up/down counter whose output is the stored welding current reference. The welding current reference is thus either increased or decreased until it reaches the value called for by the adjustable remote rheostat. After the power level has been adjusted as desired, the remote rheostat is removed from the electrode holder and placed like a pen back into the pocket of the operator.
U.S. Pat. No. 4,266,114 to Hansen issued May 5, 1981, entitled "Apparatus for the Remote Control of Mains Operated DC and AC Welding Machines", discloses a portable regulating device intended to be connected into the welding current circuit between the electrode or electrode holder and the workpiece or clamp therefor. A regulating device selectively generates different control signals in the welding cables when receiving a current supply through the welding cables. A regulating circuit in the welding machine is adapted to receive these control signals through the welding cables from the regulating device, and to cause regulation of functions in the welding machine.
The regulating circuit consists of a decoding circuit which, in response to the pulse-shape control signals in the welding cables, produces regulating signals for the welding machine, depending upon the number of pulses or the code of pulses being provided by the regulating device. A blocking circuit prevents the formation of regulating signals in the decoding circit when currents of the same order of magnitude as the welding current flow in the welding cables.
U.S. Pat. No. 4,275,266 to Lasar issued June 23, 1981, entitled "Device to Control Machines by Voice", discloses a machine which responds to a plurality of predetermined musical tones which are delivered in a sequence in order to generate a digital control output signal. The audio signal is converted to a sequence of digital number signals which are temporarily stored in a memory. Then a sequence of ratio signals are generated by performing arithmetic division in a systematic order. The resulting sequence of ratio signals is then converted to digital numbers comprising the digital control output signal. A microprocessor, with its associated storage or memory, processes the digital data and controls the conversion of the musical tones into corresponding digital numbers. The device is then made electrically connectable to an apparatus whose operation is to be voice controlled.
U.S. Pat. No. 4,340,797 to Takano and Ueda issued July 20, 1982, entitled "Voice Actuated Heating Apparatus", discloses a heating apparatus such as an electric oven which includes a voice recognition part capable of recognizing voice commands of the user. It produces a recognition code by receiving the voice command and then performing the operation commanded. Heating sequences are preliminarily stored in a memory of a control part, one of them is selected by a recognition code produced by the voice recognition part, and preset in the memory. Heating members are controlled in a manner so as to heat the object according to the preset heating sequence.
U.S. Pat. No. 4,340,799 to Ueda, Takano and Suzuki issued July 20, 1982, entitled "Heating Apparatus with Voice Actuated Door Opening Mechanism", discloses a heating apparatus such as an electric oven having an enclosure with an openable door having a locking means. A voice recognition circuit for recognizing voice commands of the user of the apparatus is connected to a releasing mechanism which permits opening the door in response to a human voice command.
The above-cited U.S. Patents are incorporated by reference into this Specification. Generally, speech recognition machines fall into two broad categories, machines which recognize either (1) isolated words, or (2) continuous speech. Because of the complexity of human speech, most research has concentrated on solving specific tasks, such as recognizing either isolated words or continuous speech with a small vocabulary. Fortunately, many practical applications exist for limited recognition. Isolated word recognition, for example, is adequate for logging freight destinations in warehouses, or identifying and counting items for inventory control.
Even though word recognition machines vary greatly in detail, they all use the same basic recognition process. First, a spoken word is converted into an electrical signal by a microphone. Second, the signal is processed to extract a set of identifying features. Third, the features are then compared to a library of templates representing the machine's vocabulary. Fourth, a word is recognized if it matches one of the templates stored in the machine's memory.
The stored reference templates are created either in a laboratory (speaker-independent), or by using the recognition machine itself in a special training mode (speaker-dependent). When training the machine with his voice, the human speaker repeats each word several times to enable the machine to compute an average template for (1) that word, and (2) that speaker (or class of speakers). The analysis stage of speech recognition consists of the voice recognition unit's extracting identifying characteristics from the electrical analog of the speech signal. Speech recognition machines are described in "Unraveling the Mysteries of Speech Recognition", Michael Elphick, High Technology, Vol. 2, No. 2, March/April 1982, pages 71-78; which is hereby incorporated by reference into this Specification.
None of the above-identified patents or articles provides a means for verbally adjusting the power level of an overall welding system, or suggests a combination which would provide for a speech-controlled power adjustment as part of a welding system.
The application of voice recognition technology to welding systems presents many problems. The higher levels of audible noise and electromagnetic interference found in the welding environment are examples of problems which adversely affect the operations of the electronic equipment required for voice recognition.
Making power adjustments manually by the welder-operator is often time consuming and costly, and is sometimes dangerous. For example, a welder on a construction crew, often several floors above the location of a welding power supply, precariously perched on scaffolding or steel I-beams and holding a welding torch, often cannot make the necessary adjustments readily. He might have to return to the ground level where the power supply is located to adjust the power output manually, he might employ an assistant to make the changes for him, or he might carry a foot pedal, connected to the welding power supply by cables, with which he can make the necessary adjustments. Alternatively, if the welder has to manually adjust a device such as that disclosed in U.S. Pat. No. 4,216,367 cited above, there is a time lag in the power adjustment as well as inconvenience to the operator in having to use his hands to make the power adjustment.
Therefore, there is a need for an apparatus and method which would permit a remotely located welder to quickly and safely adjust the power output of a welding power supply located at some distance from the welder, while welding is actually taking place.